Method of manufacturing roofing products

ABSTRACT

Methods of making roofing products. One such method includes (a) creating a mixture having a filler and a polymer; (b) forming a sheet from the mixture; (c) cooling the sheet; (d) embossing the sheet; (e) forming multiple roofing products from the sheet; and (f) bundling at least some of the roofing products. Steps (a)-(f) are performed using an automated procedure. Another of the methods involves (a) creating composite roofing products using mold cavities; (b) using a robot to transfer some of the roofing products from some of the mold cavities to a conveying system; and (c) stacking together at least two of the roofing products that have different colors or different surface configurations.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of parent application Ser. No. 10/387,823; filedMar. 12, 2003.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

The present invention relates to methods of manufacturing roofingproducts.

Traditional roofing products include asphalt shingles, wood shakes,slates, and metal panels. Each of these products has benefits. Forinstance, wood shakes and slate roofing are very aesthetic. However,wood shakes are considered a fire hazard and slate is very expensive andsubject to cracking.

Less expensive roofing products have been introduced to simulate woodshakes and slate roofing. Some asphalt shingles have been developed thatresemble slate or shake roofing. However, asphalt products typically donot have the structural rigidity of slate or shake. Metal and plasticshingles have been developed that simulate shake and slate. However,those products are subject to denting and breakage.

Composite roofing products, typically composed of at least a polymer anda filler component, have been developed to resemble certain of the moretraditional roofing products, including shakes and slates. Themanufacture of these composite roofing products has traditionallyinvolved the use of extrusion, pressing, and/or molding techniques. Anexample of a process involving extrusion of roofing products composedprimarily of asphalt appears in U.S. Pat. No. 5,690,876. Examples ofmolding processes used in making composite roofing products includethose in U.S. Pat. Nos. 6,025,052; 6,112,492; and 5,635,124. The use ofboth extrusion and molding is disclosed in U.S. Pat. No. 6,290,885.

Some of these patents promote economies of scale in aspects of theirmanufacturing. However, none discloses a manufacturing solution thattakes advantages of economies of scale and may be automated fromvirtually beginning to end.

SUMMARY OF THE INVENTION

The present invention comprises methods for creating roofing products.Certain steps of the present methods may be automated. In oneembodiment, the invention is a method of making roofing products thatcomprises (a) creating a mixture having a filler and a polymer; (b)forming a sheet from the mixture; (c) cooling the sheet; (d) embossingthe sheet; (e) forming multiple roofing products from the sheet; and (f)bundling at least some of the roofing products. Steps (a)-(f) areperformed using an automated procedure.

In another embodiment, the invention is a method of making roofingproducts that comprises (a) creating composite roofing products usingmold cavities; (b) using a robot to transfer some of the roofingproducts from some of the mold cavities to a conveying system; and (c)stacking together at least two of the roofing products that havedifferent colors or different surface configurations.

Other embodiments having additional or different steps are discussed ingreater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings demonstrate aspects of some of the presentmethods and layouts that may be used to carry out the present methods.They illustrate by way of example and not limitation. Like referencenumbers refer to similar elements.

FIG. 1 is a sheet line layout that may be used to perform embodiments ofsteps of certain of the present methods.

FIG. 2A shows one embodiment of a feeder/material handler and extrudercombination that may be used to carry out embodiments of steps ofcertain of the present methods.

FIG. 2B is a layout showing one set of equipment that may be used toperform embodiments of the bundling step of certain of the presentmethods.

FIGS. 3-5 are flow diagrams showing steps of embodiments of the presentmethods for creating roofing products.

FIG. 6 is a layout showing one set of equipment that may be used toperform certain extrusion-related steps of certain of the presentmethods.

FIG. 7 is an injection molding layout that may be used to performembodiments of steps of certain of the present methods.

FIGS. 8, 9A-9C, and 10 are flow diagrams showing steps of embodiments ofthe present methods for creating roofing products.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In this document (including the claims), the terms “comprise” (and anyform of comprise, such as “comprises” and “comprising”), “have” (and anyform of have, such as “has” and “having”), and “include” (and any formof include, such as “includes” and “including”) are open-ended linkingverbs. Thus, a method “comprising” creating a mixture having a fillerand a polymer; forming a sheet from the mixture; cooling the sheet;embossing the sheet; forming multiple roofing products from the sheet;and bundling at least some of the roofing products; where these stepsare performed using an automated procedure, is a method that possessesthe recited steps, but is not limited to possessing only the recitedsteps. For example, the method also covers cooling the sheet afterembossing it.

Likewise, a given step in a “comprising” claim covers not only what isrecited in the step, but also additional aspects that are not recited.For example, cooling the sheet covers cooling the sheet using air, andcooling the sheet using water.

The terms “a” and “an” mean one or more than one. The term “another”means at least a second or more.

Those of skill in the art will appreciate that in this detaileddescription, certain well known components and assembly techniques havebeen omitted so that the present methods are not obscured in unnecessarydetail. Dimensions provided in English units may be translated to thecorresponding metric unit by rounding to the nearest millimeter.

Sheet Line Methods

Certain of the present methods may be used in accordance with the sheetline layout shown in FIG. 1. One such method is method 200, the steps ofwhich are illustrated in FIG. 3. Step 210 of method 200 is creating amixture having a filler and a polymer. Step 210 may be carried out usingextruder 10 shown in FIG. 1. Extruder 10 may include (e.g., be connectedto) a mixer. As part of the mixture creation, the starting materials ofat least a polymer and at least a filler may be fed into extruder 10.When extruder 10 also includes a mixer, the starting materials (e.g.,polymer, filler, colorant, and other additives, if any) may be fed byfeeders and/or material handlers into a hopper of the mixer.

For example, FIG. 2A shows three feeders/material handlers 20 that maybe used to feed starting materials into a hopper 12 of a mixer(unlabeled) connected to extruder 10. Although not shown as such, thefeeder(s)/material handler(s) that are used consistent with the presentmethods may be coupled to each other in a way that allows the componentsof the eventual mixture (e.g., at least polymer and filler) to be mixedprior to being dumped into the hopper of the mixer (or hopper of theextruder if the extruder lacks a separate mixer), where additionalmixing occurs. As used in this document, two things are “coupled” ifthey are connected, but not necessarily directly and not necessarilymechanically. The mixing by one or more of the feeders and/or materialhandlers is part of one embodiment of step 210.

Also shown in FIGS. 1 and 2 is die 14, which may be a sheet die. Step220 of method 200 is forming a sheet by extruding the mixture through adie. This step may be accomplished using extruder 10 and die 14 shown inFIGS. 1 and 2.

Examples of starting materials for the mixture include polyethylene andlimestone. The polyethylene may be high- or low-density polyethylene,and may be virgin or recycled. The limestone may be crushed limestone. Acolorant may also be used as a starting material, as may other materialssuch as UV-protectors, and fire retardants. The starting materials maybe fed at ambient temperature into extruder 10. Alternatively, thestarting materials may be fed at ambient temperature intofeeders/material handlers 20. Feeders/material handlers 20 may then worktogether to mix the starting materials together, heating them to someextent (but not necessarily to a molten state) prior to dumping theminto extruder 10 or, in some cases, hopper 12 of a mixer connected toextruder 10.

Suitable extruders for use with certain of the present methods includehot-feed (i.e., the starting materials enter the extruder in a stateheated above ambient) and cold-feed (i.e., the starting materials enterthe extruder at ambient). Suitable extruders also include screw-typeextruders, such as single-screw or double-screw extruders (more screwsthan two may be used). When no mixer is attached to extruder 10 incarrying out step 210, an extruder with a screw designed to mix thestarting materials to create the mixture may be used. Alternatively,where a mixer is used in creating the mixture, the extruder may includeonly a feedscrew that is designed to pump the mixture and not contributeto the creation of the mixture.

One example of a suitable extruder for use with the present methods isFarrel's CP2500 continuous mixer (Ansonia, Conn.), which includes anexternally-heated continuous mixer on the front end and anexternally-heated extruder on the back end. One way of carrying out step210 involves the use of the CP2500. More specifically, in creating themixture, the starting materials may be compounded within the mixingchamber barrel of the CP2500. The compounding may include heating thepolymer until it reaches a molten state. The heating may be achievedusing the externally-heated mixing chamber barrel, and through thefriction between the rotors of the mixer, the mixture itself, and theinside of the barrel. As a result of the heating, the polymer mayencapsulate some or all of the filler. The temperature of the mixture atthis point may be 325 to 600° Fahrenheit (F).

Continuing with this example of creating a mixture (step 210), theheated barrel of the mixer is controllable. A maximum temperature may beset, and if the mixture exceeds that temperature, the external heaterwill trip off. A minimum temperature may also be set, and if the mixturefalls or starts off at or below that temperature, the external heater ofthe mixing chamber barrel will turn on. However, the external heater ofthe barrel will always be operating (although it may be tripped offunder the appropriate circumstances).

After creating the, step 220 of forming a sheet by extruding the mixturethrough a die, such as a sheet die, may be performed. In FIG. 1, the dieis shown generically as a point 14 on the end of extruder 10. In FIG.2A, die 14 is more visible. In carrying out step 220, extruder 10 mayforce the mixture through the die to form a sheet that then begins totravel along a conveyor, such as conveyor belt 30. The temperature ofthe sheet after exiting the die may be 225 to 500° F.

When using the CP2500, the mixture will be fed from the mixer barrel tothe extruder barrel through an enclosed connecting chute. The CP2500 isequipped with a pneumatically-operated pusher assembly for the extruderhopper that allows the mixture to be crammer-fed into the extruderbarrel. The hopper of the extruder is externally heated, as is thebarrel of the extruder.

The extruder of the CP2500 has a feedscrew that is designed to pumponly. Use of the feedscrew will raise the temperature of the mixtureminimally, if at all, although the external heaters on the extruderhopper and barrel may function to keep the mixture in a molten state tofacilitate formation of a sheet by extrusion.

One example of a die 14 that may be used for carrying out step 220 is a28-inch Masterslide HD sheet die available from Battenfeld GloucesterEngineering (Gloucester, Mass.). This die may be dimensioned to create asheet that is approximately 1/4 inch thick by 26 inches wide. Othersheets of other desired dimensions may be created using different dies.In carrying out step 220, a sheet may be formed by forcing the mixturethrough this die using the feedscrew of the extruder of the CP2500.

The sheet that is formed by step 220 may be conveyed along conveyor belt30 to calender rolls 40, oriented one above the other. Alternatively,extruder 10 and die 14 may be positioned sufficiently close to calenderrolls 40 that conveyor belt 30 is not used. Step 230, which is smoothingthe sheet, may be accomplished by passing the sheet through calendarrolls 40. Conveyor belt 30 may be driven automatically. In addition tosmoothing the sheet, the calender rolls may also reduce the thickness ofthe sheet, depending on the nip (i.e., the distance between the surfacesof the rolls) setting. The calender rolls may be stationary andunconnected to conveyor belt 30. Alternatively, calender rolls 40 may becoupled by a movable station to conveyor belt 30, such that the positionof the calender rolls may be varied along a continuous section ofconveyor belt 30. After smoothing the sheet by passing it throughcalender rolls, the temperature of the sheet may be 175 to 300° F.

One example of a pair of calender rolls suitable for use as calenderrolls 40 is a 24-inch by 32-inch Model 2000 ST Hydraulic 2-roll stackavailable from Battenfeld Gloucester Engineering (Gloucester, Mass.).The stack is equipped with electrically-powered heating and coolingelements that allow the calender rolls to be heated or cooled asdesired.

Continuing with method 200, after the sheet is smoothed, the sheet mayproceed along conveyor belt 30 to embossing station 60, which may bedesigned to impart features to the sheet for the purpose of ultimatelycreating roofing products shaped like or having the appearance ofshakes, slate, or tile. As the sheet passes to embossing station 60along conveyor belt 30, step 240 of cooling the sheet (e.g., some or allof the sheet) may be carried out using cooling station 50. Coolingstation 50 may comprise a cooling conveyor (also described as a coolingconveyor section) from EMI Plastics Equipment (Wickliffe, Ohio). Onesuch EMI cooling conveyor is Model No. RM-30-10-70, which may be used ina 10-foot section.

Alternatively, cooling station 50 may comprise an apparatus configuredto reduce the temperature of a portion of the sheet, such as a mister,which may comprise an apparatus that has multiple nozzles. When a misteris used, water mist may be sprayed out of the one or more nozzles ontothe sheet below. A drip pan may be positioned beneath the relevantportion of conveyor belt 30 to catch the water as it runs off the sheetand the conveyor belt. The water from the drip pan or pans may bechanneled automatically to a single cooler or multiple coolers, andrecycled to the nozzles of that mister.

As another alternative, cooling station 50 may comprise the combinationof a conveyor, such as a cooling conveyor, and an apparatus configuredto reduce the temperature of a portion of the sheet, such as a mister.

After step 240, the temperature of the sheet may be 150 to 250° F. Thesheet traveling along conveyor belt 30 in FIG. 1 may then be embossed(step 250) using embossing station 60, which may comprise one or tworolls. Like calender rolls 40 (sometimes referred to as a “calendarstack” in the art), embossing station 60 may be separate from and notmovable along conveyor belt 30; or embossing station 60 may be coupledto the conveyor such that the position of embossing station 60 may bevaried along a continuous section of conveyor belt 30. Embossing station60 may comprise two rolls, either or both of which may serve to emboss aportion of the sheet contacted. For example, where two rolls are used asshown in FIG. 1, the top roll in the embossing station may have atextured surface that gives the top of the sheet features that stimulateeither wood, slate, or shake. The bottom roll may be smooth or textured.As another example, the bottom roll may be provided with a surface thatis smooth except for being configured to mark information on the sheetsuch as the date, company name, style of roofing product, or one or moreof the like.

The roll or rolls of embossing station 60 may be equipped withelectrically-powered heating and cooling elements that allow them to beheated or cooled as desired. An embossing station suitable for use asembossing station 60 is a BF Perkins 2 roll face embossing machine(Rochester, N.Y.). After step 250, the temperature of the sheet may be130 to 220° F.

After step 250 of embossing the sheet, the sheet may be cooled again(step 260) using, for example, another cooling station. Cooling station52 depicted in FIG. 1 may be used to carry out this cooling (step 260),and may be configured in the same way as cooling station 50 describedabove. That is, cooling station 52 may comprise a cooling conveyor(e.g., a cooling conveyor section), an apparatus configured to reducethe temperature of the sheet (e.g., a mister), or at least both. Theytype of mister and the type of cooling conveyor described above may beused.

Alternatively, cooling station 52 may comprise two apparatusesconfigured to reduce the temperature of the sheet, the two apparatusesbeing placed side by side. The same type of mister described above maybe used for each of these two apparatuses in this example.

As another alternative, cooling station 52 may comprise two coolingconveyor sections. The same type of cooling conveyor described above maybe used in this example (e.g., two 10-foot sections).

As still another alternative, cooling station 52 may comprise twocooling conveyors, each coupled to an apparatus configured to reduce thetemperature of the sheet, such as a mister. Again, the type of misterand the type of cooling conveyor described above may be used for thisversion of cooling station 52.

After step 260, the temperature of the sheet may be 100 to 200° F.

To the extent that water is used with cooling stations 50, 52, and 54(discussed below), the cooling stations may be coupled to each other ina way that allows for water used in the cooling to be recycled. Forexample, each mister used may be coupled together and the watercollected in the drip pan or pans beneath each may be directed to acommon cooler or coolers that include a heat exchanger. Further, suchwater use may be closed (i.e., new water is not added after a certainpoint) or open (new water is added at regular intervals). One or morecooling conveyors may be used for cooling station 52 that do not involvethe use of water. Such an embodiment of cooling station 52 allows thesheet to cool in the ambient air.

After step 260 of cooling the sheet (e.g., using cooling station 52),step 270 of forming multiple roofing products from the sheet may becarried out using, e.g., cutter 70 to cut the sheet. Cutter 70 may beconfigured as a roll, the outer surface of which is provided with aseries of knives arranged to cut multiple roofing products across thewidth of the sheet. The outer surface of such a roll may also beprovided with knives that cut multiple roofing products along a givenlength of the sheet. An example of a cutter 70 that may be used informing multiple roofing products is the Compact Model Web-Fed SoftAnvil Rotary Die Cutter, available from CORFINE in Dayton, Ohio. Such acutter uses a cutting roll and a die. After step 270, the temperature ofthe roofing products may be 80 to 180° F.

Next, step 280 of cooling at least some of those roofing products(possibly all of them) may be carried out. Such cooling may take place,for example, using cooling station 54. Cooling station 54 may becomprise one or more cooling conveyors, such as forty feet (four,10-foot sections) of cooling conveyors. The EMI cooling conveyorsdescribed above may be used in this regard. Alternatively, as with theother cooling stations, apparatuses configured to reduce the temperatureof the sheet—such as misters—may be used with regular conveyors. One ormore such apparatuses may be used in this regard, and the mistersdescribed above may be used as the apparatus(es). After step 280, thecooled roofing products may be 70 to 175/F.

The position of the finished roofing products is shown as element 80 inFIG. 1.

After cooling at least some of the roofing products (which may be all ofthem) according to step 280, step 290 of bundling at least some of theroofing products (which may be all of them) may occur at station 120shown in FIG. 1. As shown in FIG. 4, one embodiment of the bundling ofstep 290 involves stacking some of the roofing products to form a stack(step 292), placing the stack on a pallet (step 294), and wrapping thestack (step 296). The stacking, placing, and wrapping steps may beaccomplished using an automated procedure. This means that the procedureis designed to accomplish the stacking, placing, and wrapping withouthuman intervention, although human intervention may be used at times toaddress malfunctions or to manually override the automation.

FIG. 2B illustrates a layout of the equipment (represented by blockdiagrams) that may be used to carry out one embodiment of steps 292-296.As FIG. 2B shows, conveyor 30 may be linked to a variable speed conveyor31 (e.g., available from Van Pak Corporation, Maryland Heights, Mo.).Variable speed conveyor 31 carries the roofing products to a robot 121that is configured to stack the roofing products into stacks 122. Robot121, therefore, may be configured to carry out step 292. The speed ofvariable speed conveyor 31 may be set with respect to the speed ofconveyor 30 so as to create space between the parts as they aredelivered to robot 121. An example of a robot suitable for use as robot121 is ABB's Industrial Robot IRB 140 (available from ABB in Vasteras,Sweden).

Robot 121 is configured to place stacks 122 in the loading queue ofstrapper 154. Strapper 154 may be configured to place one or more strapsaround stack 122. Using straps helps ensure that the roofing productsbecome and remain aligned with each other. For example, strapper 154 maybe configured to strap stack 122 across the width of the roofingproducts. The strapped stack may then be ejected from strapper 154 ontoa conveyor 32 equipped with a turning cross (represented by an “X”)(such a conveyor is also available from the Van Pack Corporation).Conveyor 32 may be configured to rotate a strapped stack 90 degrees andreturn the rotated stack to strapper 154 to be strapped again (e.g.,across the length of the roofing products). A suitable strapper for useas strapper 154 is an EAM Mosca Model TR3C 700/550 in-line strappingmachine (available from EAM-Mosca Corporation, West Hazleton, Pa.). Sucha strapping machine may be altered from its stock condition to includeguides and stops configured so as to position the stacks in the properlocation for the strapping to take place.

Alternatively, conveyor 32 may be configured to advance the strappedstack 122 to a palletizer 160. Queuing stations 156 may be provided as apart of conveyors 32 or as part of palletizer 160. These queuingstations are configured to queue strapped stacks 122 prior to thepalletizing of the stacks.

An example of a suitable palletizer for use as palletizer 160 is theSeries 2000 Gantry Palletizer available from the Van Pak Corporation.

Palletizer 160 may be equipped with one or more loading stations 158 forstacking bundles (e.g., strapped stacks 122) on one or more pallets,which may be made of wood. This process may be used to accomplish step294 of placing a stack on a pallet. Palletizer 160 may be equipped witha gantry-style robot to pick up an incoming bundle with vacuum cups anddeliver it to a pallet on the loading station 158. The robot may beconfigured to place bundles on a pallet in multiple orientations to bestensure that the pallet is mechanically stable. For example, the robotmay be configured to rotate a bundle placed on top of another bundle by90°.

Once a pallet has been loaded with bundles (e.g., a given pallet onpalletizer 160 may be configured to hold 10 rows of bundles, and eachrow may include 6 bundles), the loaded pallet may be ejected from theloading station by a powered chain conveyor 162 (available from the VanPak Corporation) and delivered by a shuttle conveyor and dual conveyorshuttle car system 165, which are available from the Van PakCorporation. Shuttle conveyor and dual conveyor shuttle car system 165may be configured to accept loaded pallets from palletizer 160 anddeliver them to wrapping station 167. The process for this transfer ofthe loaded pallets from the palletizer to the wrapping station involvesthe dual shuttle car shifting on its shuttle conveyor to align with theloading station that is ready to deliver a loaded pallet, accepting thatloaded pallet, and then shifting along its shuttle conveyor to alignwith power chain conveyor 38, which communicates with wrapping station167. Empty pallets may be loaded into one or more pallet dispensers 169,which can then transfer the empty pallets back to one or more loadingstations 158 for use by palletizer 160.

The wrapping step (296) of the present sheet line methods may be carriedout at, for example, wrapping station 167, which may include a stretchwrapper 171, such as the model FA-66 Orion Automatic Stretch WrappingMachine having a heat seal option (available from Orion PackagingSystems, Inc. in Collierville, Tenn.). Wrapping film made be fed tostretch wrapper 171 from its supply wheel 173. Loaded pallets are thenwrapped (e.g., stretch wrapped) using stretch wrapper 171. The wrappedpallet may then be ejected onto a powered chain conveyor (available fromthe Van Pak Corporation) and queued. A lift truck 175 may then take thewrapped pallet to storage.

As shown in FIG. 5 with method 300, step 298, which is recycling scrapfrom the cutting of step 270, may be carried out by collecting scrapfrom the sheet and routing them back to extruder 10 along anotherconveyor (not shown in FIG. 1). The scrap may then be placed back intoextruder 10. This recycling may start at one or more locations alongconveyor belt 30 (see also FIG. 5). For example, FIG. 1 shows that scrapmay be taken at points 90 (at cutter 70) and 100 (beyond cooling station54), and routed back to extruder 10 as indicated by arrow 110. One wayin which this recycling may be achieved at point 90 involves scrapmaterial falling away from conveyor 30 after the sheet is cut toanother, underlying conveyor. The underlying conveyor (not shown) maythen route the scrap to a grinder, also not shown (e.g., a RapidGranulator Model R-36, available from Rapid Granulator, Inc. inRockford, Ill.). The grinder then grinds the scrap material to a desiredstate. Next, the ground scrap may be conveyed to a storage bin for useat an appropriate future time. At the desired time, which may be presetas part of an automated process, the ground material may be transportedfrom the bin to a feeder, such as feeder/material handler 20 shown inFIG. 2A, for re-introduction into mixer 10. This transportation may takeplace in any suitable way, including, for example, by a vacuumconnecting the bin to the feeder.

Some or all of the steps of methods 200 and 300 may be performed usingan automated procedure. This means that the steps performed in thismanner are designed to be accomplished without human intervention,although human intervention may be used at times to address malfunctionsor to manually override the automation. Step 210 of creating a mixturehaving a filler and a polymer will, when using an automated procedure,be understood not to exclude steps that involve human intervention toplace starting materials in the appropriate locations from which theremainder of the creating can occur.

Injection Molding Methods

Certain of the present methods may be used in accordance with theinjection molding-related layouts shown in FIGS. 6 and 7. One suchmethod is method 400, the steps of which are illustrated in FIG. 8. Step410 of method 400 is creating multiple roofing products using moldcavities. The term mold cavities does not include what are known in theart as dies. Carrying out step 410 may be achieved in a variety of ways.

One way involves use of the pelletizing layout shown in FIG. 6. Extruder10, which may be, in one embodiment, the CP2500 discussed above, may beused to create a mixture having a polymer and a filler (such as thepolymer and filler discussed above) in the manner discussed above. Themixture may then be pushed through pelletizer 310 (FIG. 6) and cut usingpelletizer 310 to form pellets 320. This process of creating pellets maybe referred to as pelletizing the mixture. A suitable pelletizer is aGala Industries, Inc. underwater pelletizer model MAP-7 (Eagle Rock,Va.). This pelletizer may be attached to the end of extruder 10.

The size of pellets 320 created using pelletizer 210 may be betweenabout 0.110 and 0.150 inches in diameter. Other diameters may be moresuitable for other applications. The temperature of the mixture goinginto the pelletizer, may be about 350 to 400° F. The temperature of theresulting pellets may be about 100 to 150° F.

As shown in FIG. 6, pellets 320 may then be dried using dryer 325. Dryer325 is useful where pellets 320 have been created using an underwaterpelletizer, such as the Gala pelletizer discussed above. However, wherepellets 320 are not created using a liquid in any way, dryer 325 may notbe used. When the pellets are finished drying, their temperature may beabout 80 to 150° F. A suitable dryer for use as dryer 325 is the GalaCentrifugal Pellt Dryer Model 16.3 BF ECLN, available from GalaIndustries, Inc. After drying, pellets 320 may be routed to storage, asindicated by arrow 335.

Pellets 320 may be taken from storage, or routed directly from dryer325, and placed in one or more injection molders 330 shown in FIG. 7 incontinuing this exemplary process of carrying out step 410. Eachinjection molder 330 that is used may include a mixing barrel designedto raise mix the pellets and raise the temperature of the pelletmaterial (e.g., the mixture referenced above) to a molten state, or 350to 500° F. Each injection molder 330 that is used may include asingle-screw with a barrel that is externally heated to do this. Theheating of the pellets may occur by the external heater of such abarrel, and by the friction created between the screw rotor, the pelletmaterial, and the inside of the screw barrel. If a colorant is used, itmay be added during the mixing of the pellet material in a giveninjection molder 330.

FIG. 7 shows two injection molders 330 being used. It should beunderstood, however, that as few as one injection molders may beutilized consistent with the present methods, provided the injectionmolder includes a mold having two or more cavities. Further, as manyinjection molders 330 as desired may also be used—such as 15, forexample. Colorant may be added using a volumetric or gravimetric colorfeeder, such as the Thoresen McCosh WSB-260T (available from ThoresonMcCosh in Troy, Mich.), that is coupled to one or more of the injectionmolders 330. An injection molder suitable for use as one of theseinjection molders is the Van Dora HT Model 500 injection molder (VanDora Demag Corporation, Strongsville, Ohio).

Continuing with a description of how one injection molder 330 works(with the understanding that multiple injection molders may be used andthat this description applies to as many as are used), from injectionmolder 330, the mixture will be heated and injected into the moldcavities 340. If only one injection molder 330 is used, multiple moldcavities 340 (e.g., two, three, or more) should be used consistent withthe present methods. If multiple injection molders 330 are used, eachinjection molder may have as few as one mold cavity 340, although two,three, or more mold cavities 340 may be used in each of the multipleinjection molders. Throughout this disclosure, however, a single block340 in each injection molder 330 represents one or more mold cavities,and this description will sometimes discuss the operation and use of asingle mold cavity 340 in explaining the present methods.

Mold cavity 340 may be cast or machined to have one or more surfacesconfigured to resemble shakes, slates, or tiles. Mold cavity 340 may bemade in two, three, or more pieces, and made be made of metal, such asP20. Mold cavity 340 may be machined to have a surface or surfacesformed using digitized modeling. The digitized model may be of thetarget roofing product, such as a shake, slate, or tile. Each moldcavity 340 may be configured to produce a separate roofing product.

As part of step 410, the roofing products created using mold cavities340 may be cooled by running water or another suitable coolant throughthe mold cavities. This type of cooling may serve to restrict the flowof the mixture into the mold cavity. The amount of mixture to be placedin each mold cavity may be determined by weight or volume, which isdetermined substantially by the desired size and shape of eachindividual part.

After step 410, and after the roofing products in mold cavities 340 havebeen sufficiently cooled, such as down to 70 to 170° F., step 420 maytake place. Step 420 is transferring some of the roofing products fromsome of the mold cavities to a conveyor or to multiple conveyors, suchas conveyor belts 30 in FIG. 7, using one or more robots, such as robots360. Each robot 360 may be positioned about the clamp (not shown) of aninjection molder 330. Once the molding process is complete and theproduct is ready to be removed from the mold cavities, the clamp ofinjection molder 330 will open and robot 360 will remove the finishedpart or parts from the mold cavity or cavities. Robot 360 may then movealong a beam 361 that allows it to translate between injection molder330 and conveyor 30. Robot 360 may place the part on conveyor 30, whereit will travel to a packaging area. As shown in FIG. 7, beams 361 may beconfigured to allow the robot of each injection molder to access eitherconveyor 30. Examples of suitable conveyor belts for use as conveyors 30in FIG. 7 are TEC's Classic Steel Horizontal Conveyors (available fromTEC Engineering, Oxford, Mass.).

Recycling of scrap material (i.e., step 460 of method 600 shown in FIG.10) may also be started at this point. One way of recycling scrapinvolves another conveyor, such as conveyor 37 (which may be a TECClassic Steel Horizontal Conveyors available from TEC Engineering),positioned along the path accessible on beam 361 by robot 360. As robot360 travels along its beam, it may stop at conveyor 37, break off anyrunner attached to the finished product it is transporting, and placethat runner or other scrap material onto conveyor 37. Conveyor 37 maythen transport that scrap material to a grinder 370 (e.g., RapidGranulator Model R-36, available from Rapid Granulator, Inc. inRockford, Ill.). After the scrap material is ground using grinder 370,it may be transported by vacuum to a storage bin 372, which may storethe ground scrap for use at an appropriate future time. At the desiredtime, which may be preset as part of an automated process, the groundmaterial may be transported from the bin to a blender 374 in anysuitable manner, such as by vacuum. Blender 374 may then re-mix theground scrap with any other desired materials and deposit mixture backinto the feed throats of one or more of the injection molders 330.

A suitable robot for use as robot 360 is the Sailor model RZ-300N2S-M3L(available from Sailor USA Inc., Kennesaw, Ga.). Although not shown witha cooling station or stations such as those described above, conveyorbelts 30 may be equipped with such cooling stations in order to cool theroofing products placed on conveyor belts 30 by robots 360.

Each injection molder 330 may be configured to product finished roofingproducts of a certain color. The mold cavity or cavities 340 in eachinjection molder 330 will produce the same colored roofing products as aresult. Different injection molders may be configured to produce roofingproducts with different colors.

After step 420, at some point, at least two roofing products with eitherdifferent colors or different surface configurations will be positionedbeside each other on a conveyor belt 30. By different colors we mean twocolors that have different hues, different values, or different chromaon the Munsell scale. Our use of “different” in the terms “differentcolors” and “different surface configurations” does not include thosedifferences due to chance. The differences to which we refer are thosethat are purposefully created.

Such different products will then travel along conveyor belts 30 tostation 190, where step 430 may be carried out. Step 430 is stackingtogether at least two of the roofing products that have different colorsor different surface configurations. Two such stacks are represented inFIG. 7 as elements 376. Of course, more than two roofing products may beincluded in such a stack; however, at least two of them must havedifferent colors or different surface configurations.

Another of the present methods, method 500 illustrated in FIG. 9A,involves additional use of, for example, station 190. In addition tosteps 410-430, method 500 includes taking the stack created through step430 and placing the stack on a pallet (step 440). Method 510 shown inFIG. 9B includes steps 410-440 of method 500, and additional step 450 ofwrapping the stack. Method 520 shown in FIG. 9C includes steps 410-450of method 510, and the additional step 445 of placing a strap around thestack, which as described below may take place prior to the wrapping ofthe stack. As in the case of steps 292, 294, and 296 discussed above,the stacking, placing, strapping and wrapping steps of methods 500-520may be accomplished using an automated procedure, as this phrase wasdefined above.

Returning to FIG. 7, one example of the equipment (represented by blockdiagrams) that may be used for station 190 to accomplish one or more ofsteps 430, 440, 445, and 450 of FIGS. 8-9C is shown. As FIG. 7 shows,each conveyor 30 may be linked to a variable speed conveyor 31 (e.g.,available from Van Pak Corporation, Maryland Heights, Mo.). Eachvariable speed conveyor 31 carries the roofing products to a stacker150. The speed of variable speed conveyor 31 may be set with respect tothe speed of conveyor 30 so as to create space between the parts as theyare delivered to the stacker 150. An example of a suitable stacker is aVan Pak Vertical Stacker (aka a Lowerator) from the Van Pak Corporation(Maryland Heights, Mo.). Stacker 150 stacks multiple finished roofingproducts (e.g., up to 15). Stacker 150 may be configured to carry outstep 430 of stacking at least two roofing products with different colorsor surface configurations together to create stack 376. The number ofstackers 150 used will depend on the number of incoming conveyors3—generally, there is a one-to-one correspondence.

As shown in FIG. 7, each stacker 150 may be provided with a queuingstation 151 into which stacks 376 are inserted. Stacker 150 may thenindex downwardly and deliver a given stack 376 onto another conveyor 152that transports the stack to a strapper 154. Suitable conveyors forconveyor 152 are available from the Van Pak Corporation.

Strapper 154 may be configured to carry out step 445 by placing one ormore straps around stack 376. Using straps helps ensure that the roofingproducts become and remain aligned with each other. For example,strapper 154 may be configured to strap stack 376 across the width ofthe roofing products. The strapped stack may then be ejected fromstrapper 154 onto a conveyor 32 equipped with a turning cross(represented by an “X”) (such a conveyor is also available from the VanPack Corporation). Conveyor 32 may be configured to rotate a strappedstack 90 degrees and return the rotated stack to strapper 154 to bestrapped again (e.g., across the length of the roofing-products). Asuitable strapper for use as strapper 154 is an EAM Mosca Model TR3C700/550 in-line strapping machine (available from EAM-Mosca Corporation,West Hazleton, Pa.). Such a strapping machine may be altered from itsstock condition to include guides and stops configured so as to positionthe stacks in the proper location for the strapping to take place.

Alternatively, conveyor 32 may be configured to advance the strappedstack 376 to a palletizer 160. Queuing stations 156 may be provided as apart of conveyors 32 or as part of palletizer 160. These queuingstations are configured to queue strapped stacks 376 prior to thepalletizing of the stacks.

An example of a suitable palletizer for use as palletizer 160 is theSeries 2000 Gantry Palletizer available from the Van Pak Corporation.

Palletizer 160 may be equipped with one or more loading stations 158 forstacking bundles (e.g., strapped stacks 376) on one or more pallets,which may be made of wood. This process may be used to accomplish step440 of placing a stack on a pallet. Palletizer 160 may be equipped witha gantry-style robot to pick up an incoming bundle with vacuum cups anddeliver it to a pallet on one of the loading stations 158. The robot maybe configured to place bundles on a pallet in multiple orientations tobest ensure that the pallet is mechanically stable. For example, therobot may be configured to rotate a bundle placed on top of anotherbundle by 90°.

Once a pallet has been loaded with bundles (e.g., a given pallet onpalletizer 160 may be configured to hold 10 rows of bundles, and eachrow may include 6 bundles), the loaded pallet may be ejected from theloading station by a powered chain conveyor 162 (available from the VanPak Corporation) and delivered by a shuttle conveyor and dual conveyorshuttle car system 165, which are available from the Van PakCorporation. Shuttle conveyor and dual conveyor shuttle car system 165may be configured to accept loaded pallets from palletizer 160 anddeliver them to wrapping station 167. The process for this transfer ofthe loaded pallets from the palletizer to the wrapping station involvesthe dual shuttle car shifting on its shuttle conveyor to align with theloading station that is ready to deliver a loaded pallet, accepting thatloaded pallet, and then shifting along its shuttle conveyor to alignwith power chain conveyor 38, which communicates with wrapping station167. Empty pallets may be loaded into one or more pallet dispensers 169,which can then transfer the empty pallets back to one or more loadingstations 158 for use by palletizer 160.

The wrapping step (450) of the present injection molding methods may becarried out at, for example, wrapping station 167, which may include astretch wrapper 171, such as the model FA-66 Orion Automatic StretchWrapping Machine having a heat seal option (available from OrionPackaging Systems, Inc. in Collierville, Tenn.). Wrapping film made befed to stretch wrapper 171 from its supply wheel 173. Loaded pallets arethen wrapped (e.g., stretch wrapped) using stretch wrapper 171. Thewrapped pallet may then be ejected onto a powered chain conveyor(available from the Van Pak Corporation) and queued. A lift truck 175may then take the wrapped pallet to storage.

Some or all of the steps of methods 400, 500, and 600 may be performedusing an automated procedure, as “automated procedure” was definedabove. Step 410 of creating multiple roofing products using moldcavities will, when using an automated procedure, be understood not toexclude steps that involve human intervention to place startingmaterials in the appropriate locations from which the remainder of thecreating can occur.

The purpose of stacking together different roofing products withdifferent colors (not different colors within a given roofing product,but different colors of different roofing products) or different surfaceconfigurations is to provide builders/roofers with the option of easilyapplying such differently-colored or configured roofing products to asingle roof. This is an attractive option where the different colorsdiffer by chroma or value. The convenience of not needing to mix theroofing products from one pallet with the roofing products of anotherproduct on site in order to achieve a multi-colored roof or a roof thatincludes roofing products with different textures is one that is notenjoyed in the prior art.

The steps of the present methods need not be carried out exactly asdescribed above to fall within the scope of the claims and theirequivalents. For example, the cooling of the sheet may be carried outusing pressurized air, as opposed to pressurized water or ambient air.

The claims are not to be interpreted as including means-plus- orstep-plus-function limitations, unless such a limitation is explicitlyrecited in a given claim using the phrase(s) “means for” or “step for,”respectively.

1. (canceled)
 2. (canceled)
 3. (canceled)
 4. (canceled)
 5. A method ofmaking roofing products comprising: (a) creating a mixture having afiller and a polymer; (b) forming a sheet by extruding the mixturethrough a die; (c) smoothing the sheet; (d) cooling the sheet using afirst cooling station; (e) embossing the sheet; (f) cooling the sheetusing a second cooling station; (g) forming multiple roofing products bycutting the sheet; (h) cooling at least some of the roofing products;and (i) bundling at least some of the roofing products.
 6. The method ofclaim 5, where (i) comprises: (j) stacking at least some of the roofingproducts to form a stack; (k) placing the stack on a pallet; and (l)wrapping the stack; where (j)-(l) are performed using an automatedprocedure.
 7. The method of claim 6, where (i) further includes: (m)placing a strap around the stack; and where (j)-(m) are performed usingan automated procedure.
 8. The method of claim 5, further comprising:(j) recycling scrap from the cutting.
 9. A method of making roofingproducts comprising: (a) creating composite roofing products using moldcavities; (b) using a robot to transfer some of the roofing productsfrom some of the mold cavities to a conveying system; and (c) stackingtogether at least two of the roofing products that have different colorsor different surface configurations.
 10. The method of claim 9, where(c) forms a stack, and the method further comprises: (d) placing thestack on a pallet.
 11. The method of claim 10, further comprising: (e)wrapping the stack; where (c)-(e) are performed using an automatedprocedure.
 12. The method of claim 11, further comprising: (f) placing astrap around the stack; where (c)-(f) are performed using an automatedprocedure.
 13. The method of claim 9, where at least one of the moldcavities has a surface formed using digitized modeling.
 14. The methodof claim 5, wherein steps (a)-(h) are performed using an automatedprocedure.
 15. A method of making roofing products comprising: (a)creating a mixture having a filler and a polymer; (b) forming a sheet byextruding the mixture through a die; (c) smoothing the sheet; (d)cooling the sheet using a first cooling station; (e) embossing thesheet; (f) cooling the sheet using a second cooling station; (g) formingmultiple roofing products by cutting the sheet; (h) cooling at leastsome of the roofing products; and (i) bundling at least two of theroofing products that have different colors or different surfaceconfigurations.
 16. The method of claim 15, where (i) comprises: (j)stacking at least some of the roofing products to form a stack; (k)placing the stack on a pallet; and (l) wrapping the stack; where (j)-(i)are performed using an automated procedure.
 17. The method of claim 16,where (i) further includes: (n) placing a strap around the stack; andwhere (j)-(m) are performed using an automated procedure.
 18. The methodof claim 15, further comprising: (j) recycling scrap from the cutting.